Bucket



June 23, 1936. J. D, RENFROE BUCKET Filed July 24, 1954 INvENTOR. James D.Renfroc ATTORNEY.

Patented June 23, 1936 UNITED STATES BUCKET James D. Renfroe, Old Hickory, Tenn., assigner to Du Pont Rayon Company, New York, N. Y., a corporation of Delaware Application July 24, 1934, serial No. 736,669

3 Claims.

This invention relates to an improved process for the treatment of artificial thread, filaments, straw, ribbon, or the like. More particularly, it relates to an improved process for washing bucket cakes of artificial silk thread, and to apparatus useful for carrying out this process.

In the washing of bucket cakes of artificial silk by centrifugal methods known heretofore, great difficulty has been encountered in elliciently and uniformly washing the bucket cake. Such prior art processes, among other limitations, fail to remove eciently the undesirable materials contained therein such as salt, acid and other materials present in the bath liquor or formed as reaction products, which .are retained in the bucket cake after the spinning operation. Ineflicient removal of these undesired materials variously affects the yarn and results in the production of bucket cakes which are spotted or stained, particularly in that portion of the cake which is disposed at the bottom of the washing bucket where penetration of the cake with washing liquor is very difiicult and proceeds very slowly. f

It is therefore an object of this invention to provide an eflicient and economical method and apparatus for the liquidl treatment of-bucket cakes of artificial thread.

A further object of this invention comprises an efficient method and .apparatus for centrifugally washing bucketcakes. Another object of the invention is'to provide a new type of centrifugal bucket in which the cake is washed more rapidly, eiciently, and uniformly than heretofore.

Other objects and advantages of this invention will become apparent from the following detailed description, taken in connection with the details illustrated in the accompanying drawing, in which:

Fig. l is a vertical sectional view of a centrifugal bucket constructed in accordance with this invention;

y Fig. 2 is a similar vertical sectional view of a modified form of bucket;

Fig. 3 is a fragmentary view, partially in section, of a spray nozzle;

Fig. 4 is a perspective view of a modified form of spray nozzle.

In the production of artificial threads, lilaments, ribbon, straw, or the like, by the bucket process, a suitable cellulosic solution, e. g. viscose, is extruded into a coagulating and regenerating bath wherein it is converted into a continuous cellulosic product of the desired crosssectional area `and shape. This bundle of -laments or thread or the like is drawn from the bath, is twisted and is deposited in the form of a cross wound package of yarn in a rapidly revolving bucket. When the thread or the like is Wound under the action of high centrifugal force, i. e. in large diameter buckets or buckets revolving at very high speeds, and continuously for a long period of time, as in the present practice, the bucket cakes are quite thick and com pact, making it difficult to remove the undesirable products of reaction and the salt, acid, and perhaps other materials comprising the coagulating liquor carried by the thread and contained inV the cakes. This invention in its preferred form relates to the removal of these undesirable materials by a centrifugal washing operation.

The invention will be described in connection with the accompanying drawing.

The bucket cakes, which are to be washed, are deposited in a centrifugal bucket I which is provided with an upwardly extending Wall 8, pref-V erably sloping outwardly to a slight degree. Wall 8 is provided with a plurality of apertureslor drain holes I3 through which the water is thrown from the bucket after having passed through the bucket'cakes. The base of the bucket is provided With a cake-supporting ledge II which slopes upwardly towards the wall 8. The central portion of the base comprises a circular depression I0 into which a portion of the washing liquid may drain. Drain apertures I4 are provided in the base of the bucket adjacent the peripheral edge of the depression I 0 in order to draw off the washing liquor continuously so that it will not accumulate in the bucket. Y

The bucket is further provided with a downwardly extending hub 9 by means of which the bucket may be driven in any suitable manner, for example, by means of a hollow drive shaft IB connected to an electrically driven motor (not shown) A spray nozzle I'I is adapted to be projected up through the hollow drive shaft I6 into the bucket and thereby be centrally positioned within the cake 3U which preferably is provided with a protective but permeable wrapping 3 I, for instance, of cheese cloth. Extending upwardly from the central portion of the depression I0 and surrounding the spray pipe I'I is a protecting collar I2 adapted to prevent the liquid from entering the motor through the hollow drive shaft I6;

Spray pipe I'I is provided with a plurality of perforations or apertures I8 from which the Washing liquid under pressure is directed against the interior of the bucket cake 30. The liquid spray from the lowerrnost apertures of the spray pipe Il, as shown in Fig. 1, will be directed against the sloping surface of the cake-supporting ledge Il, thereby being splashed or being deflected upwardly against the lower, outer portion of the cake 3D, whereby the lower, outer portion of the cake will be thoroughly washed.

The centrifugal bucket l containing the bucket cake is rotated at a relatively high rate of speed, for example, 4000-8000 R. P. M., this speed depending to a certain extent upon the denseness and thickness of the bucket cake and the conse-v quent diiculty of forcing the washing liquid through the cake. The washing operation may be completed in the space of a few minutes with the production of a washed cake which is uniformly free from undesirable materials.

In lieu of the spray nozzle, illustrated in Fig. 1 of the drawing and described above, any conventional form of spray pipe or nozzle may be used. Thus, for example, where a stationary spray pipe or nozzle is used, the openings i8 may be of varying size and may be variously spaced. These variations are shown in Fig. 3 where the spray pipe I9 is provided with perforations or openings 20 through which the washing water is impelled toward the inner surface of the bucket cake, openings 20 being spaced to a greater degree towards the middle portion of the spray nozzle and being closer together at the top and bottom portions of the nozzle. In the form of nozzle shown in Fig. 3, openings 20 may be varied in size, for example, the holes at the upper and lower portions of the spray pipe may be of a smaller diameter than those located at the central portion thereof or vice versa.

Another modification of spray pipe which operates eiiiciently is illustrated in Fig. 4 of the drawing. In this modification, the spray pipe 2|, having spaced openings 22 arranged in a single substantially vertical line, is provided with a liquid-direction deiiector 23, the wash liquid flowing from openings 22 and impinging against the deiiector 23, being thereby directed toward the cake 30 in the form of a solid sheet of liquid or of dense spray.

A modified form of centrifugal bucket is illustrated in Fig. 2, the wash water being introduced into the bucket by a conventional overhead traversing nozzle 28 having a liquid-discharging aperture 29. This form of bucket is designated generally by reference character 25 and is provided With a sidewall 8 substantially identical with that shown in the modification of Fig. l. Bucket 25 is driven by a solid motor drive shaft 2l, and is provided with a cake-supporting ledge l I which may have a somewhat steeper slope than that shown in Fig. 1. The bottom central portion of the bucket may be substantially flat instead of being depressed as shown in Fig. 1, as illustrated at 26, the base of the bucket being provided with liquid draw-off passages i4 which prevent accumulation of the wash water in the bucket.

The present invention deals particularly with a new system for centrifugally Washing bucket cakes. It will be understood, however, that the invention may be similarly applied to liquidtreating operations other than washing, for example desulfuring and/or bleaching operations, where the treatment liquid is other than water. In fact, a bucket cake may be successively washed,

desulfured and bleached, if desired, without being removed from the bucket, and, additionally, it may be subjected to whizzing after each liquid treatment to remove the adhering liquid from 4the cake. By way of illustration of this extension to a water line for washing purposes, to a desulfuring liquor container, and to a bleaching liquid container. Each of these conduits may be opened and closed by hand at the proper time, or, alternatively, all the operations may be carried on automatically. During the automatic operation of the various processing steps, the motors for driving the bucket and for pumping the spray liquid into the bucket may be independently operated according to a pre-determined time cycle and the various valves for controlling the flow of the different treating-liquids may likewise be operated according to a time cycle of pre-determined length. In this way, the entire treatment of the cake may be carried on automatically without it being removed from the centrifugal bucket. Such an automatic system may be operated and controlled exclusively by electrical energy through a suitable timing device, or, alternatively, mechanical operating means may be used.

The invention is applied with particular benefit to the treatment of regenerated cellulose thread in the form of bucket cakes as obtained by the viscose process. It will be understood that the invention is not so limited, however, being similarly applicable to the treatment of bucket cakes of artificial thread obtained by other processes, for example, the cuprammonium cellulose process.

Inasmuch as the description and drawing are merely illustrative, any variation or modification thereof which conforms to the spirit of the invention is intended to be included within the scope of the claims.

I claim:

l. A centrifuging bucket for the liquid treating of artificial silk thread comprising a circular side wall and a thread supporting base inclined upwardly toward the side wall at a substantial angle, whereby treating liquid will be deflected upwardly against the said thread, a spray means projecting upwardly through said base, said base having acentral, downwardly offset portion, and an annular upwardly directed flange surrounding said spray means.

2. A process for the liquid treating of artificial silk thread which comprises revolving a spun cake of thread at a high rate of speed, directing a horizontal stream of treatment liquor against the inner surface of said cake, and splashing a stream of treatment liquor against the bottom surface of said cake.

3. A process for the liquid treating of artificial silk thread which comprises revolving a spun cake of thread at a high rate of speed, directing a horizontal stream of treatment liquor against the inner surface of said cake, splashing a stream of treatment liquor against the bottom surface of said cake, and draining the excess treatment liquor from a point below the bottom of said cake. 70

JAMES D. RENFROE. 

